Recently, there has been increasing consideration given to the possibility of using, as an alternative to traditional cardiac-valve prostheses, valves designed to be implanted using minimally-invasive surgical techniques or endovascular delivery (so-called “percutaneous valves”). Implantation of a percutaneous valve (or implantation using thoracic-microsurgery techniques) is a far less invasive act than the surgical operation required for implanting traditional cardiac-valve prostheses.
These expandable prosthetic valves typically include an anchoring structure or armature, which is able to support and fix the valve prosthesis in the implantation position, and prosthetic valve elements, generally in the form of leaflets or flaps, which are stably connected to the anchoring structure and are able to regulate blood flow. One exemplary expandable prosthetic valve is disclosed in U.S. Publication 2006/0178740 A1, which is incorporated herein by reference in its entirety.
An advantage of these expandable prosthetic valves is that they enable implantation using various minimally invasive or sutureless techniques. One non-limiting exemplary application for such an expandable valve prosthesis is for aortic valve replacement. Various techniques are generally known for implanting such an aortic valve prosthesis and include percutaneous implantation (e.g., transvascular delivery through a catheter), dissection of the ascending aorta using minimally invasive thoracic access (e.g., mini-thoracotomy), and transapical delivery wherein the aortic valve annulus is accessed directly through an opening near the apex of the left ventricle. Note that the percutaneous and thoracic access approaches involve delivering the prosthesis in a direction opposing blood flow (i.e., retrograde), whereas the transapical approach involves delivering the prosthesis in the same direction as blood flow (i.e., antegrade) Similar techniques may also be applied to implant such a cardiac valve prosthesis at other locations (e.g., a pulmonary valve annulus).
Further problems in the art include positioning the prosthetic valve in the right location as well as centering the valve prior to implantation.
There is a need in the art for delivery and implantation instruments capable of delivering an expandable prosthetic valve to a precise location associated with a corresponding valve annulus. There is a further need for instruments adapted to carefully control expansion of the valve to prevent the valve from misaligning during valve expansion. Finally, there is a need for an instrument adapted to remove such a prosthetic valve.